83b6ec3

[WTF] Make UTF-8 StringImpl::create defensive against concurrent content modification
https://bugs.webkit.org/show_bug.cgi?id=311771
rdar://173601233

Reviewed by Mark Lam and Sosuke Suzuki.

It seems that some of JSC clients are using StringImpl::create wrongly,
and modifying the passed content concurrently. Previously, it was a bit
gracefully handled without SIMDUTF, but new code requires this invariant
more strictly and getting release-assert when this is broken. Modifying
concurrently is not allowed and that's a client bug, but anyway, let's
make it a bit defensive against such a behavior. This patch uses
pre-allocated maximally-possible sized Vector and using
simdutf::convert_utf8_to_utf16 instead.

* Source/WTF/wtf/text/StringImpl.cpp:
(WTF::StringImpl::create):

Canonical link: https://commits.webkit.org/310857@main

5a68384

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